DIETARY PHYTOHEMAGGLUTININ SLOWS DOWN THE PROLIFERATION OF A MOUSE PLASMACYTOMA (MPC-11) TUMOR IN BALB C MICE/

Ten days after subcutaneous injection of MPG-11 cells, plasmacytoma tu mours which developed in female Balb/c mice fed on a diet containing t he kidney bean lectin phytohaemagglutinin (PHA) at a concentration of 7.0 mg g(-1) diet, weighed only about 38% of those fed a lactalbumin ( La) control diet. The reduction in growth caused by the lectin appeare d to occur in a dose-dependent manner but the values did not reach sig nificance before PHA was at a concentration of 7.0 mg g(-1) diet. Pre- feeding with the lectin caused a further 50% reduction in tumour weigh t. In contrast to the reduction in tumour size the inclusion of PHA in the diet elevated the mean dry weight of the small intestine in a dos e-dependent manner, values reaching significance at 3.5 mg g(-1) diet. The results showed that gut hyperplasia was able to occur even in the presence of the developing tumour. A lypolytic effect of PHA occurred at high concentration. The observations suggest that PHA itself does not have a direct effect on the tumour cells, but an inter-relationshi p between gut hyperplasia and decreased tumour growth is indicated.